Update Refresh Rate for M62
atrac17 opened this issue · 3 comments
Greeting! @ElectronAsh, @paulb-nl, or @alanswx would you be willing to adjust the vertical refresh rate for the M62 to core? Proper timings appear to be 56.338028 Hz for 256 (visible) horizontal titles. This has been updated in the mame 0234 for 256p titles.
It'll help with sync issues on CRT's amongst other things. I've also seen this referenced in manuals for Kung Fu Master. It was mentioned in #14 for Kung Fu Master.
According to Mame it appears that Hi-res games (Lode runner) use a 24.0Mhz clock which results in 8Mhz÷512÷284 = 55.01760Hz.
Low res games use a 18.432Mhz clock which results in 6.144Mhz÷384÷284 = 56.338028Hz.
The different clocks could be switched with pll_reconfig but the problem is that the pll also generates the 3.579545Mhz ÷ 4 audio clock. That one needs to be generated from a separate pll or in another way.
@paulb-nl Above is what I have too ÷ by 3 for the two clocks. But based on this:
<machine name="kungfum" sourcefile="m62.cpp">
<display tag="screen" type="raster" rotate="0" width="256" height="256" refresh="56.338028" pixclock="6144000" htotal="384" hbend="128" hbstart="384" vtotal="284"
<machine name="kidniki" sourcefile="m62.cpp">
<display tag="screen" type="raster" rotate="0" width="384" height="256" refresh="55.017606" pixclock="8000000" htotal="512" hbend="64" hbstart="448" vtotal="284" vbend="0" vbstart="256"/>
(Edit: We are saying the same thing. It's time for bed).
I noticed that while this core has a pal option, it would be nice to also have a force to 57 and 60hz as well ... Reading the above though I'm gathering kung fu master should be running at nearly 57hz anyway?